CHT Graetz Submit
cht_graetz_submitReplace plug-flow Nusselt estimates with a laminar flow-coupled Graetz simulation in Elmer and validate the fitted thermal decay against the exact Graetz eigenvalue.
Instructions
Flow-coupled Graetz channel via Elmer (SIMULATION_NEXT B4), asynchronous — the TRUE Nusselt validation that upgrades cht_channel_submit's plug flow: FlowSolve computes the real laminar profile and HeatSolver rides on it (Convection = Computed) between two isothermal walls. Requires ElmerSolver; when absent this returns {ok:false, reason, install} rather than raising.
Two gates: the solved parabola's u_max/u_mean ≡ 3/2 exactly, and the developed
mixing-cup decay d ln(T_wall−T_bulk)/dx fitted over the second half of the
channel yields Nu, gated against the Graetz eigenvalue Nu_T = 7.5407 (parallel
plates, constant wall temperature) — a slug profile would give π² = 9.87, so
the gate also proves the profile coupling is real. This closes the loop with
the h_estimate correlation screen. The writer polices Re < 400, development
lengths inside the first 45 %, and cell Péclet ≤ 25. Also accepts a prepared
case_dir.
Returns the degradation dict or {job_id, status, cache_hit}; poll job_result for {ok, u_max_over_mean (≈1.5), nu_fit, nu_exact, nu_ratio (≈1, ±10 %), nu_slug, reynolds, prandtl, pe_cell, case_dir}.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| nx | No | ||
| ny | No | ||
| sif | No | case.sif | |
| gap_m | No | ||
| t_in_c | No | ||
| k_fluid | No | ||
| case_dir | No | ||
| cp_fluid | No | ||
| length_m | No | ||
| mu_fluid | No | ||
| t_wall_c | No | ||
| rho_fluid | No | ||
| velocity_m_s | No |